Slack adjuster



C. J. NASH SLACK ADJUSTER Feb. 13, 1934.

Original Filed Sept. 24, 1928 2 Sheets-Sheet l 1934- c. J. NASH i,947,35

SLACK ADJUSTER Original Filed Sept. 24, 1928 2 Sheets-Sheet 2 9,, 22 23 W m/m llllll k N Y \J 6 24k 25 HM E F 5&1

Patented Feb. 13, 1934 STATES PATENT ()FFICE SLACK ADJUSTER Charles J. Nash, Chicago, 111., assignor to Uni-' versal Draft Gear Attachment 00., a corporation of Illinois 24 Claims.

This invention relates to brake mechanism; and has for its principal object to provide simple means for regulating the mechanism with respect to brake shoe clearance; to prevent buffing shocks from disturbing the regulation, and to provide convenient means for indicating the condition of regulation.

Further objects and advantages of the invention will become apparent as the disclosure proceeds and the description is read in connection with the accompanying drawings, in which Fig. 1 is a somewhat diagrammatic plan view illustrating an application of the invention in connection with the dead cylinder lever of the conventional form of foundation brake gear in common use on freight cars;

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1;

Fig. 3 is a perspective view of a buttress forming one part of the attachment;

Fig. 4 is a similar view of a rider or fulcrum element;

Fig. 5 is an enlarged plan view showing the arrangement with respect to the fulcrum of the dead cylinder lever;

Fig. 6 is a vertical section taken on the line 66 of Fig. 5, illustrating the parts in normal position;

Fig. 7 is a similar view showing the positions the parts assume during brake regulation.

These specific illustrations and the correspondingly specific description are used for the purpose of disclosure only, for it is realized that the substance of the invention may be embodied in other forms and put to other applications which it is intended to include within the claims.

Referring to Fig. 1, 10 and 11 indicate draft sills of the car underframe, mounted on trucks including wheels 12, to which brake shoes 13 are applied by dead levers 14 and live levers 15, receiving power from live cylinder lever 16 and dead cylinder lever 17 through connections 18. One end of the live cylinder lever is operatively connected with the push rod 19 of an air cylinder 20, and transmits power to the dead cylinder lever through a cylinder lever connection 21.

Brake mechanisms of this general character are in common use. and their operation in the application of brakes is familiar.

The specific attachment used to illustrate the preferred form of this invention is best illustrated in Figs. 3, 4, 5, 6 and '7, and takes the place of the ordinary fixed fulcrum of the dead cylinder lever 17. It includes a guide or rack 22, hav ing we end, 23, secured to the draft sill 11 by a.

bracket 24, and the other end bent to form an arm 25, which is secured to a cross-sill 26.

The body portion of the rack is rectangular in cross-section, as best illustrated in Fig. 5, and the teeth 27 are carried on the narrow top edge.

A rider or fulcrum element, generally indicated at 28 in Figs. 1 and 4, and a buttress, generally indicated at 29 in Figs. 1 and 3, cooperate with each other and the rack to adjust the fulcrum of the dead cylinder lever and thereby adjust the brake mechanism. Those familiar with this sort of mechanism will understand that movement of the fulcrum of the dead lever 17 to the left in Fig. 1 will adjust the mechanism to compensate for wear on the brake shoes and the like, and that a return to the right should be made to provide clearance for new brake shoes.

The rider 28 which may also be termed a fulcrum block includes a box-like frame comprising a top 30, bottom 31, and ends 32, 33, the top and bottom being perforated at 34 to receive a pin 35, which forms the actual fulcrum for the lever 17. From Figs. 1, 4, 5, 6 and 7 it will be clear that the lever extends through the box-like frame of the rider 28, and has its projected end 36 formed into a handle.

Flanges 3'7 and 38, extending downwardly from the bottom 31, are connected at their lower ends by a web 39, and, together with the bottom, form a stirrup or yoke telescoping with the rack 22 and permitting the rider to move lengthwise with respect to the rack in the brake regulating operations. The flange 37 is substantially at one edge of the bottom, and the flange 38 is considerably removed from the opposite edge. Consequently, the box-like frame projects laterally with respect to the rack 22.

The buttress 29 (Fig. 3) or ratchet block includes end portions having rectangular open frames 40 and 41, receiving the rack 22 at spaced apart points. The bottom of the upper wall 42 of the frame 40 is provided with teeth 43 to cooperate with the teeth 27 on the rack. The vertical dimensions of the frames 40 and 41 exceed the vertical dimensions of the rack suificiently to provide clearance for the disengagement of the teeth when adjustments are to be made. For this reason the teeth act as a pawl and for convenience, the buttress will be described as equipped with a pawl.

The web 39 of the rider or fulcrum element (Fig. 4) is extended as an arm 44, and is adapted to pass between the lower surface 45 (Fig. 6) of the rack 22 and the upper surface 46 of the bottom 47 of the frame 40, thereby locking the teeth 43 in engagement with the teeth 27 and holding the parts firmly in the position shown in Fig. 6 except during regulating movement. The under side of the arm 44 is beveled at 48 to facilitate its entry between the rack and the buttress frame, and beyond the beveled portion it has a flattened end portion 49, which remains in the frame in the extreme position shown in Fig. 7, to serve as a guide when the parts are to be returned to the position shown in Fig. 6.

The top portionof the buttress (Fig. 3) is of channel form, and its web 50 and flanges 51 are bent downwardly and blend with the ends of the buttress. The right end is extended laterally by a flange 52, reenforced by gussets 53 and 54, and thus provides a broad bearing for the end 32 of the rider 28. The bottom of the buttress is T- shape in cross-section, and both its base 55 and flange 56 are bent upwardly and blended with the ends of the buttress.

The normal position of the parts is clearly illustrated in Figs. 1, 5 and 6, from which it will be obvious that in a brake application by air the buttress 29 prevents the rider 28, and therefore the fulcrum pin 35, from moving to the right. And from Fig. 6 it will obvious that the'arm 44 holds the teeth 43 in engagement with the teeth 47 and prevents the buttress from being shifted in buffing and similar operations.

Regulation is effected by rotating the dead cylinder lever 17 to the left in Figs. 1 and 5, which may be accomplished by grasping the handle 36, or in any other convenient manner. In this movement the foundation brake gear operates to bring the shoes 13 toward the wheels 12, while the rider 28 is moving from the position shown in Fig. 6 toward the position shown in Fig. 7. If the brake clearance is proper the brake shoes should be firmly pressed against the wheels as the wall 33 of the rider comes against the left end of the buttress. If there is excess clearance the lever 17 can rotate still farther, taking the rider still further toward the left and the buttress with it, when the teeth l3 will rise over the teeth 47, as illustrated in Fig. 7,-the movement being continued until the shoes are firmly pressed against the wheels, when the lever 17 is returned to the right or merely released and left to as sume such position when the brakes are next applied by air.

As the lever returns in its clockwise movement the rider or fulcrum element 28 will return to the position shown in Fig. 6, and the arm 44 will edge itself between the end frame 40 and the rack and bind the parts firmly in the adjusted position.

The difference in length between the box-dike portion of the rider 28 and the top of the buttress will be made proportional to normal brake shoe clearance, and will be varied to suit diiferent brake mechanisms. When new brake shoes are to be applied the parts are first put in the condition substantially as shown in Fig. 7, and afterward the buttress and rider are moved togethe to the right.

The term "fulcrum element as it is used in this specification is intended to be construed broadly and to include any member or part thereof which functions as or assists some other part in functioning as a fulcrum. For example, it is meant to include a bralr lever which is so associated with the other parts or" the adjusting mechanism that a fulcrum for the lever is effected. Also, it is intended to include a member which is connected to a brake lever, even though remotely, in such manner that the point of connection with the lever is made a fulcrum of the lever.

The term pawl is likewise used in a broad sense and is intended to include any member or part of a member having one or more teeth adapted to engage some other member and hold it against some particular kind of movement, and it is unimportant whether the pawl member is pivoted or otherwise held in position for engagement with the other member.

The above definitions of terms are, of course, limited by the prior art, and if necessary, should be narrowed to their proper scope in view of the art.

I claim as my invention- 1. In 2. brake mechanism, a normally fixed buttress adjustable to regulate the mechanism, a fulcrum element having free movement relative to the buttress limited to a distance corresponding to normal brake shoe clearance, and means associated with the fulcrum element for positively holding the buttress fixed during movement of the fulcrum elem nt preliminary to a regulating adjustment of the buttress.

2. In a brake mechanism, a bar, a buttress adjustable with respect to the bar to regulate the mechanism, a fulcrum element having free movement with respect to the buttress limited to a distance corresponding to normal brake shoe clearance, and an arm on the fulcrum element preventing adjustment of the buttress during operation of the brake gear and during movement of the fulcrum element preliminary to regulating v the adjustment or" the buttress.

3. In a brake mechanism, a bar, a buttress adjustable with respect to the bar to regulate the mechanism, a fulcrum element having free movement with respect to the buttress limited to a distance corresponding to normal brake shoe clearance, and an arm on the fulcrum element preventing adjustment of the buttress until the fulcrum element has moved in one direction relative to the buttress a distance correu spending to normal brake shoe clearance.

4. In a brake mechanism, a rack, a buttress looped about the rack and adjustable with respect to the rack to regulate the mechanism, a fulcrum element, and an arm on the fulcrum element, extending between the rack and the buttress to prevent adjustment of the buttress until the fulcrum element has had a preliminary movement corresponding to normal brake shoe clearance.

5. In a brake mechanism, a rack, a buttress having a tooth engaging the rack and relatively adjustable to regulate the brake mechanism, a fulcrum element including an arm preventing disengagement of the tooth from the rack until the fulcrum element has moved in one direction relative to the rack a distance corresponding to normal brake shoe clearance.

63. In a brake mechanism, a rack having teeth, a buttress having a tooth to engage the rack, a

stirrup on the buttress cooperating with the rack,

and including means to prevent adjustment of the buttress relative to the rack when the fulcrum element is in its normal operative position.

8. In a brake mechanism, a rack, a buttress telescoping with the rack and adjustable relatively thereto for regulating the mechanism, a fulcrum element telescoping with the rack, and an arm on the fulcrum element preventing relative adjustment of the buttress on the rack until after a preliminary relative movement of the fulcrum element.

9. In a brake mechanism, a rack, a buttress including end portions telescoping with the rack, and an intermediate portion spaced from the rack, a fulcrum element telescoping with the rack between the end portions of the buttress, and means associated with the fulcrum element to prevent relative adjustment of the buttress until the fulcrum element has had a preliminary movement relative to the buttress.

10. A slack adjuster for car brake systems comprising a bar, a series of ratchet teeth on its upper face, a fulcrum block slidably mounted on the bar, means for pivotally attaching a brake lever to the fulcrum block, a ratchet block mounted upon the bar and having ratchet teeth cooperating with the teeth thereof and being engageable by the fulcrum block on brake applications, and means for preventing movement of the ratchet block independently of the fulcrum block.

11. A manually actuated regulator for brake rigging comprising a normally fixed ratchet rod, a member embracing said rod at two separated points, a fulcrum element cooperating with said rod and mounted between said two points, the effective distance between one point and said fulcrum element being proportional to brake shoe clearance, and a pawl cooperating with said ratchet rod normally held in locked position by said element when the parts are in normal position of rest.

12. A manually actuated regulator for brake rigging comprising a ratchet rod, a cage mounted upon said ratchet rod and adapted to move relative thereto, a pawl carried by the cage cooperating with the ratchet rod, and a fulcrum element within the cage normally holding the pawl in locked relation, said cage and fulcrum element providing a lost motion movement proportional to brake shoe clearance whereby the brake shoes are brought substantially into engagement with the peripheries of the wheels before the pawl is released from its locked position.

13. In a brake mechanism a fixed rack, a buttress adjustable along the rack to compensate for wear and including end portions telescoping with the rack and an intermediate portion spaced from the rack, a dead brake lever having movement along the rack between the end portions of the buttress a distance proportional to brake shoe clearance and movable with the buttress in excess of that distance, and means associated with the lever to prevent adjustment'of the buttress along the rack until the lever has had a preliminary movement.

14. In a brake mechanism, a rack, a buttress including end portions telescoping with the rack, and an intermediate portion spaced from the rack, a dead brake lever mounted between the end portions of the buttress adapted to move the buttress along the rack when and if excess travel exists and providing a predetermined free movement of the lever proportional to brake shoe clearance prior to a regulating action on the brake mechanism, and means associated with the dead brake lever to prevent relative adjustment of the buttress until the lever has had a preliminary movement relative to the buttress.

15. In a foundation brake gear including a live cylinder lever and a dead cylinder lever, the combination of means to adjust the brake gear to compensate for wear including a relatively fixed rack, a buttress movable along the rack, a pawl carried by the buttress and engaging the rack, a fulcrum element having limited movement with respect to the buttress and a fulcrum on the element for the dead cylinder lever.

16. In a foundation brake gear, including a live cylinder lever and a dead cylinder lever, the combination of means to adjust the brake gear to compensate for wear including a relatively fixed rack, a buttress movable along the rack, a pawl carried by the buttress and engaging the rack, a lock for the pawl, a fulcrum element having limited movement with respect to the buttress and a. fulcrum on the element for the dead cylinder lever.

17. An attachment for brake gears including a guide adapted to be made fast to a car, a buttress on the guide, means for securing the buttress to the guide in a plurality of positions, a fulcrum element associated with the buttress, said buttress and fulcrum co-operating to permit the fulcrum element to have a limited movement with respect to the buttress corresponding to normal piston travel.

18. An attachment for brake gears including a guide adapted to be made fast to a car, a rack on the guide, a buttress on the guide, a pawl on the buttress adapted to engage the rack, a pawl lock adapted to engage the guide and hold the pawl in engagement with the rack, a fulcrum element on the buttress and a fulcrum for a dead cylinder lever on the element.

19. In a foundation brake gear including a live cylinder lever and a dead cylinder lever, the combination of means for adjusting the brake gear to compensate for wear including a relatively fixed rack, a buttress movable along the rack, a pawl carried by the buttress and engaging the rack, a lock for the pawl, a fulcrum element having a limited movement with respect to the buttress corresponding to normal piston travel and adapted to automatically release the pawl look upon a given movement of the element, and a fulcrum for the dead cylinder lever associated with the element.

20. In combination with a dead brake lever, brake adjusting mechanism associated with said lever and including a relatively fixed rack, a buttress mounted on and movable along the rack, pawl mechanism carried by the buttress and engaging the rack, a fulcrum element independently mounted on and slidable along the rack having a limited movement with respect to the buttress, said buttress forming a positive stop for the element in one direction and being movable by the element in the opposite direction to effect the adjustment.

21. In a foundation brake gear including a live cylinder lever and a dead cylinder lever the combination of means to adjust the brake gear to compensate for wear including a relatively fixed rack secured to a ear member, a normally fixed buttress mounted on and movable along the rack to regulate the mechanism, a fulcrum element associated with the fulcrum of the dead cylinder lever having free movement relative to the buttress limited to a distance corresponding to normal brake shoe clearance, and means for positively holding the buttress fixed preliminary to a regulating adjustment of the buttress.

22. In a foundation brake gear including a live cylinder lever and a dead cylinder lever, the combination of means to adjust the brake gear to compensate for wear including a relatively fixed rack secured to a car member, a normally fixed buttress mounted on and movable along the rack to regulate the mechanism, a fulcrum element associated with the fulcrum of the dead cylinder lever having free movement relative to the buttress and means for positively holding the buttress fixed preliminary to a regulating adjustment of the buttress.

23. In a foundation brake gear including a live cylinder lever and a dead cylinder lever, the combination of means to adjust the brake gear to compensate for wear including a relatively fixed rack, a buttress mounted on and adjustable along the rack, and a fulcrum element serving as a fulcrum for the dead lever mounted on the rack and engageable by the buttress in both directions of movement thereof.

24. In a foundation brake gear including a live cylinder lever and a dead cylinder lever, the combination of means to adjust the brake gear to compensate for wear including a relatively fixed rack, the fulcrum end of the dead lever being mounted for movement along the rack, a pawl engaging the rack, means for locking the pawl to the rack when the lever is in its normal operative position, said locking means being arranged so that the pawl may be released only after the lever has had a preliminary movement.

CHARLES J. NASH. 

